Airflow Path Analysis And Space Pressure Management In Outpatient Area Of General Hospital

There are complex disease types and large human traffic in the outpatient area of general hospital,so that it is a place where susceptible population is highly concentrated and multiple infection sources are existing at the same time.Once cross-infection occurs inside,the recovery of patients and the health of medical staff will be affected.Airborne transmission is one of the most important ways to trigger cross-infection,therefore,maintaining the pressure difference between clean area and contaminated area in the outpatient department to control a reasonable airflow path can reduce the risk of cross-infection and ensure the safety of indoor environment in the hospital.This paper mainly studies the design requirements and current situation of airflow path and pressure control in the outpatient area of general hospital,then finds the debugging schemes for the current situation through numerical simulation.Firstly,summarize the pressure control requirements and indoor environment design parameters of relevant department rooms of the outpatient area of general hospital by doing literature research and consulting the hospital building design standards in the US,Japan,Germany and China.According to the function and composition of the outpatient area of general hospital and the treatment process and human traffic flow,divide clean-dirt partition for each department to obtain a reasonable interior airflow path and pressure control requirements of each room.Secondly,test the indoor temperature and humidity,the concentration of CO₂ and the pressure of door opening of different kinds of room on site in six general hospitals’outpatient area in Chongqing during summer,transition season and winter.Compare the test results with the hospital building design standards in the US,Japan and China.After analyzing it was found that in the actual operation condition,the temperature and humidity could not meet the corresponding season’s design parameters of in many rooms;the CO₂ concentration exceeded 1000ppm in the densely-spaced room;the pressure requirements were non-ideal in some rooms requiring pressure control,which leads to chaotic airflow path in the outpatient area and increases the risk of cross-infection.Finally,taking the pediatric diagnosis and treatment area of outpatient department in F hospital as the research object,the physical model of the area was established using the measured parameters in ICEM 16.0 software,and the RNG k-εturbulence model and SIMPLEC algorithm were selected for numerical solution in Fluent 16.0 software,and the measured indoor average temperature and the door-slot airflow velocity under operating conditions in winter were compared with the simulation results to verify the reliability of the numerical model.Simulate the indoor environment parameters under the summer condition using the measured air conditioning parameters in summer as the boundary conditions of ventilation.It is found that the airflow path and space pressure in the area could not meet the design requirements during the actual operation.Therefore,two debugging schemes are proposed.The simulation analysis shows that room differential pressure should be controlled by running the ventilation and air-conditioning system and closing the door and window in the winter and summer and the transition season;when the area’s clean-dirt partition is reasonable and every room is operating under the design air volume,the design pressure can be maintained;when it is not possible to avoid the positive pressure requirement room（cleaning area）and the negative pressure requirement room（pollution area）,it is necessary to consider the pressure infiltration and reset the air volume according to the actual layout to maintain the design pressure and ensure the rationality of the airflow path and reduce the risk of cross-infection.